Late Filing Penalty Calculator UK

Estimate Self Assessment late filing penalties from the filing deadline, actual filing date and tax due, including the fixed, daily, six-month and twelve-month penalty stages.

Estimate Self Assessment Late Filing Penalties

Filing Deadline

For many online Self Assessment returns, the usual deadline is 31 January after the tax year. Date Return Is Filed

Enter the date the return is actually filed or the date you are checking. Tax Still Due For Percentage Penalties

GBP

Six-month and twelve-month late filing penalties can include 5% of tax due, subject to a GBP 300 minimum in the standard case. Twelve-Month Behaviour

The calculator models the standard published structure. Deliberate withholding can lead to higher penalties and needs HMRC-specific review.

Penalty Estimate

GBP 1,300.00

The return is 196 days late, so the estimate includes the fixed penalty, daily penalties and the six-month penalty.

Days late196

Fixed GBP 100 penaltyGBP 100.00

Daily penalties after 3 monthsGBP 900.00

Six-month penaltyGBP 300.00

Twelve-month penaltyGBP 0.00

This estimates late filing penalties only. Late payment interest and late payment penalties are separate.

Penalty Method Used

fixed penalty = GBP 100 if the return is latedaily penalty = GBP 10 per day after 3 months, up to 90 dayssix-month penalty = greater of GBP 300 or 5% of tax duetwelve-month standard estimate = greater of GBP 300 or 5% of tax duetotal estimate = fixed + daily + six-month + twelve-month penalty

The calculator uses the common Self Assessment late filing structure: a fixed penalty once the return is late, daily penalties after the three-month point, then further penalties at six and twelve months. The date logic counts full calendar days after the filing deadline. If the return is filed on the deadline date, the result is zero. If it is filed the next day, the fixed penalty stage begins.

The six-month and twelve-month stages use the greater of GBP 300 or 5% of tax due in the standard estimate. HMRC can charge higher twelve-month penalties in some behaviour-based cases, particularly where information is deliberately withheld. This page therefore marks behaviour risk but does not try to decide HMRC behaviour categories.

Penalty Stage Table

Stage	When It Can Apply	Standard Amount	Important Boundary
Initial late filing	Return filed after the deadline	GBP 100	Can apply even if there is no tax to pay.
Daily penalties	More than 3 months late	GBP 10 per day, up to 90 days	Maximum standard daily total is GBP 900.
Six-month penalty	More than 6 months late	Greater of GBP 300 or 5% of tax due	Tax due can raise the amount above GBP 300.
Twelve-month penalty	More than 12 months late	Greater of GBP 300 or 5% of tax due in the standard case	Higher penalties may apply in serious behaviour cases.

What This Calculator Does Not Include

Late Payment Charges

Late payment interest and late payment penalties are separate from late filing penalties. A person can file late, pay late, or both. Do not use a filing-only result as a full HMRC debt estimate.

Appeals And Reasonable Excuse

HMRC may consider appeals where there is a reasonable excuse. This page cannot decide whether an appeal will succeed. Keep evidence and use the official route if you appeal.

Partnerships And Other Returns

Different return types can have different rules. This page is written for Self Assessment late filing, not corporation tax, VAT, PAYE, Companies House accounts or partnership allocation detail.

Behaviour-Based Cases

The standard twelve-month estimate may not fit cases where HMRC treats the failure as deliberate. If the return is very late or HMRC has opened contact, get proper tax advice.

Worked Examples

A taxpayer files an online Self Assessment return 20 days late. The estimate is GBP 100 because the return is late, but it has not reached the three-month stage. If there is no tax to pay, the fixed filing penalty can still apply.

A taxpayer files 150 days late with GBP 2,500 tax due. The result includes GBP 100 fixed penalty plus daily penalties from day 91 to day 150, which is 60 days at GBP 10, giving GBP 600. The six-month stage has not yet been reached, so the total estimate is GBP 700.

A taxpayer files 220 days late with GBP 10,000 tax due. The fixed penalty is GBP 100. Daily penalties reach the maximum GBP 900. The six-month penalty is the greater of GBP 300 or 5% of GBP 10,000, so it is GBP 500. The standard late filing estimate is GBP 1,500 before any late payment charges.

A return more than twelve months late with GBP 1,000 tax due has the fixed GBP 100, maximum GBP 900 daily penalties, a six-month GBP 300 penalty and a standard twelve-month GBP 300 penalty. The estimate is GBP 1,600 before payment-related charges.

How To Use The Result

Use the estimate to decide urgency, cash planning and whether to check HMRC notices. If the return is not filed, filing it is usually the first practical step because daily penalties and later stages can continue to build. If the return has already been filed, compare the calculator with HMRC’s penalty notice and check the deadline, filing date and tax due used.

Keep filing receipts, submission references and correspondence. If you believe a penalty is wrong, the dates and evidence matter. If you had a serious event that stopped you filing on time, read the official reasonable-excuse guidance and consider an appeal within the time limit. This page cannot decide the appeal; it only explains the arithmetic.

Checking HMRC Notices Against The Estimate

If a penalty notice arrives, compare it line by line with the stage table. Confirm the filing deadline, the date HMRC says the return was received, the number of daily penalty days, and the tax due used for percentage penalties. A notice can also include payment-related amounts, so do not compare a full HMRC balance with this filing-only calculator.

If the return was filed through software, keep the successful submission receipt rather than only a screenshot of a draft return. If an agent filed for you, ask for the submission reference and date. For an appeal, write a clear timeline with dates, evidence and the reason the return could not be filed on time. A short, dated record is usually stronger than a vague explanation months later.

FAQ

Can I get a GBP 100 penalty if I owe no tax?

Yes. The initial Self Assessment late filing penalty can apply even when there is no tax to pay.

When do daily penalties start?

Daily penalties can apply once the return is more than 3 months late. They are GBP 10 per day up to 90 days in the standard structure.

Does this include late payment interest?

No. It estimates late filing penalties only. Interest and late payment penalties are separate.

What if I have a reasonable excuse?

You may be able to appeal through HMRC’s official process. The calculator cannot decide whether an excuse will be accepted.

Why does tax due matter at six and twelve months?

The standard six-month and twelve-month penalties can be the greater of GBP 300 or 5% of tax due, so a larger unpaid tax figure can increase the penalty.

Can this be used for Companies House late filing?

No. Companies House accounts penalties use a different system. This page is for Self Assessment late filing estimates.

Sources

HM Revenue and Customs. (n.d.). Self Assessment tax returns: penalties. GOV.UK. https://www.gov.uk/self-assessment-tax-returns/penalties
HM Revenue and Customs. (n.d.). Appeal a Self Assessment penalty for late filing or late payment. GOV.UK. https://www.gov.uk/tax-appeals/penalty
HM Revenue and Customs. (n.d.). Self Assessment tax returns. GOV.UK. https://www.gov.uk/self-assessment-tax-returns